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September '26 Infectious Diseases Update

Posted by Doug Black, PharmD., Ann Lloyd, PharmD. on Sep 8th 2026

Article of the Month (Editors' Choice) 

The POET II Trial

By Brian S. Schwartz, M.D.

  • The POET II trial (N Engl J Med 2026 Aug 28. doi: 10.1056/NEJMoa2607887) was an international, open-label, randomized trial evaluating shorter antibiotic courses for clinically stable adults with left-sided infective endocarditis. The 508 participants had native- or prosthetic-valve endocarditis caused by S. aureus (123 patients), E. faecalis (94), or streptococci (291); one third had undergone cardiac surgery. Before randomization, all patients had completed a pathogen- and complexity-specific minimum duration of therapy (2–4 weeks) and met stringent POET stabilization criteria: no planned cardiac surgery, improving or low neutrophil counts and C-reactive protein, procalcitonin <0.5 ng/L, temperature <38°C for two days, and transesophageal echocardiography showing no disease progression. Antibiotics were then stopped immediately in the response-tailored group but continued to the conventional total duration of 4–6 weeks in the control group.
  • Response-tailored treatment reduced the median antibiotic duration from 41 to 26 days and increased time alive without antibiotics by 13 days. The primary safety composite of death, unplanned cardiac surgery, or symptomatic embolism occurred in 8.2% of the tailored group and 10.7% of the standard-duration group, meeting the prespecified noninferiority criterion. However, relapse was significantly more frequent after tailored therapy: 5.1% versus 1.6% (absolute difference, 3.5 percentage points; P=0.04). Outcomes differed by pathogen. For S. aureus, the safety composite occurred in 4.9% versus 11.3%, while relapse occurred in 4.9% versus 1.6% with tailored and standard therapy, respectively. For streptococci, the corresponding rates were 8.5% versus 12.1% for the safety composite and 3.5% versus 1.3% for relapse. The most concerning findings were with E. faecalis: safety events occurred in 11.5% versus 4.8% and relapse in 9.6% versus 2.4%, although this subgroup was underpowered and confidence intervals were wide.
  • POET II should not yet prompt routine shortening of endocarditis therapy. Its findings may support carefully selected, shorter courses for stable patients with streptococcal, or possibly S. aureus, endocarditis, provided the same stringent clinical, laboratory, and echocardiographic criteria and close post-treatment monitoring can be reproduced. Several results warrant caution: Patients with immunodeficiency were excluded and few had injection-drug use. Most importantly, the increased relapse rate—particularly the nearly 10% rate with shortened treatment of E. faecalis—suggests that standard-duration therapy should remain preferred for enterococcal endocarditis and that broader adoption for other pathogens should await confirmation or incorporate shared decision-making that explicitly addresses the tradeoff between approximately two fewer weeks of therapy and a higher risk of relapse.

New Drug Approvals

  • Bixlenvo*, a 2-drug combination of bictegravir (BIC) and lenacapavir (LEN), indicated as a complete regimen for the treatment of HIV-1 infection in adults to replace the current antiretroviral regimen in those who are virologically suppressed (HIV-1 RNA <50 copies/mL) on a stable regimen with no known or suspected resistance to BIC or LEN. The dosing schedule requires a 2-day initiation regimen of one Bixlenvo tablet plus LEN 600 mg taken once daily, followed by a maintenance regimen of one Bixlenvo tablet once daily (all tablets with or without food). One tablet of Bixlenvo contains 75 mg of BIC and 50 mg of LEN. 

Dolutegravir in Infants

  • The FDA has approved the 5 mg dispersible tablets of dolutegravir (Tivicay PD) for use (in combination with other antiretroviral agents) in infants (treatment-naive, or treatment-experienced but naive to INSTI treatment) born at term and weighing at least 2 kg. For age 0 to 14 days, the recommended dose is 5 mg every other day; for age 15 to <28 days, the recommended dose is 5 mg once daily. No data are available for preterm neonates.

New or Updated Guidelines

Antimicrobial Stewardship

Using persuasion in antimicrobial stewardship and infection prevention

  • A newly published review summarizes the literature on influence and negotiation for infection prevention (IP) and antimicrobial stewardship (AMS) leaders.
  • The domains reviewed include building relational power, framing and contrast, credibility, concreteness, social proof, urgency, and consistency. Each section includes
    specific tips for improving competency. An example suggestion is to move beyond reporting raw data by interpreting antibiotic use and resistance data in plain language. A summary of the key principles is provided in Table 1.
  • AMS and IP leaders should consider incorporating the evidence-based communication methods suggested by this article to improve their effectiveness. Antimicrob Steward Healthc Epidemiol. 2026;6:(1)e248. doi:10.1017/ash.2026.10837.

Antimicrobial Shortages (US)

  • New shortages:
    • Tuberculin skin test (PPD) (21 Aug 2026)
  • Resolved shortages:
    • Peginterferon alfa-2a (Pegasys)
  • Antimicrobial drugs recently discontinued: 
    • None
  • Antimicrobial drugs or vaccines in continued reduced supply or unavailable due to increased demand, manufacturing delays, product discontinuation by a specific manufacturer, or unspecified reasons: 
    • Antibacterial drugs:
      • Aminoglycosides:
        • Gentamicin injection (22 Feb 2021)
      • Cephalosporins:
        • Cefazolin injection (4 Jun 2018)
        • Cefotaxime injection (10 Jun 2015)
      • Fluoroquinolones:
        • Levofloxacin injection in D5W (29 May 2024)
        • Levofloxacin oral solution, 25 mg/mL (15 Sep 2023)
        • Moxifloxacin injection (13 Jan 2026)
        • Moxifloxacin 400 mg tablets (6 Dec 2023)
      • Glycopeptides, glycolipopeptides, lipopeptides:
        • Vancomycin injection (1 Jun 2015)
      • Lincosamides:
        • Clindamycin phosphate injection (25 Jun 2015)
      • Macrolides, azalides:
        • Azithromycin injection (6 Jan 2026)
        • Azithromycin oral suspension, 1 gm packets (20 Nov 2024)
        • Erythromycin lactobionate injection (21 Apr 2025)
      • Miscellaneous
        • Bacitracin ophthalmic ointment 500 units/gm (12 Sep 2024)
        • Benzylpenicilloyl polylysine [Pre-pen] (19 Mar 2026)
        • Chloramphenicol injection (9 Oct 2023)
        • Neomycin and Polymyxin B sulfates GU irrigant (25 Jun 2023)
        • Rifaximin 200 mg tablets (11 Apr 2024)
      • Oxazolidinones:
        • Linezolid injection (16 Oct 2024)
      • Penicillins:
        • Amoxicillin, all oral formulations (18 Oct 2022)
        • Amoxicillin-clavulanate, all oral formulations (17 Nov 2022)
        • Dicloxacillin 250 mg, 500 mg capsules (18 Aug 2021)
        • Penicillin G benzathine injection (1 Feb 2023)
        • Penicillin G benzathine/Penicillin G procaine (31 Mar 2023) 
    • Antifungal drugs: 
      • Amphotericin B Lipid Complex (5 Aug 2022)
      • Ibrexafungerp 150 mg tablets (3 Dec 2024)
    • Antimycobacterial drugs: 
      • Rifampin injection (26 Jul 2026)
    • Antiparasitic drugs:
      • Nitazoxanide oral susp 100 mg/5 mL (15 Feb 2024)
    • Antiviral drugs: 
      • Acyclovir injection (16 Dec 2025)
      • Oseltamivir, all formulations (1 Nov 2022)
      • Ribavirin for inhalation solution (23 May 2023)
  • For more information including estimated resupply dates, see ASHP Drug Shortages website.
  • Data shown are current as of 4 September 2026.
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